Dirk85, in your scenario you have been despatched legally, you are now indeed requiring inflight planning from that point onwards.
Generally inflight planning is more forgiving as it is not factored by 60%, but it IS taking the more actual conditions into account (not so at planning stage hence the factor is applied). Thus you do not need the 60% required at planning anymore, you are to apply inflight performance and thus can land in your scenario on any runway where inflight performance enables you to land on.